Radiator assembly



Feb. 18, 1941. A. F. HUBBARD RADIATOR ASSEMBLY Filed April 11, 19158 2 Sheets-Sheet l Q vw Feb. 18, 1941. A, F HUBBARD 2,231,915

RADIATOR AS SEMBLY Filed April ll, 193B 2 Sheets-SheetI 2 Patented Feb. 18, 1941 UNITED STATES PATENT' OFFICE 2,231,915 RADIATOR ASSEMBLY poration of Illinois l Application April 11, 1938, Serial No. 201,234

18 Claims.

The present invention in general relates to heat exchange devices and is in particular concerned with a radiator assembly of novel construction, which is especially suitable for use in air conditioning and Ventilating apparatus.

It is a primary object of the herein described invention to provide a radiator that is especially adapted foi` throttled operation when utilized for the conditioning of cold outdoor air which may at times have a temperature below freezing.

It is a further object to provide a radiator in which heat Will be distributed throughout its full length, even at extremely low steam pressures.

A further object of the invention is to provide an improved radiator in which the main flow of steam will be from end to end of the radiator in a plurality of serially connected passes, and which includes improved means for bleeding auxiliary steam into the passes to prevent freezing of condensate during throttled operation and assures heating of the radiator from end to end during low pressure operation.

Another object is to provide in a radiator improved means for removing air therefrom.

' Still another object of the invention is to provide in a radiator improved means for preventing the tubes from becoming completely lled with water in the event that the radiator is flooded.

A still further object is to provide a radiator having an improved 1in and tube arrangement of such construction that extremely low resistance will be offered to the circulation of a fluid medium thereover, and in which a high heat transfer may be effected.

@ther objects and features of the invention will more fully appear from the following detailed description taken in connection with the accompanying drawings, which illustrate a single embodiment thereof, and in which:

Figure 1 is an enlarged fragmentary horizontal sectional view taken through a radiator embodying the features of the present invention, and showing the cooperative relationship of the various parts thereof;

Figure 2 is a transverse sectional view through the inletheader, taken substantiallyl on line II--II of Figure 1;

Figure 3 is a similar view taken through the outlet header, taken substantially on line III-III of Figure 1;

Figure 4 is a fragmentary longitudinal section of the radiator, taken substantially on line IV-IV of Figure 3; and

Figure 5 is an enlarged detail sectional view showing details of the connection for the tube end caps, taken substantially on line V-V of Figure 4.

As shown on the drawings:

Referring to Figure 1 of the drawings, it will be seen that the ends of the radiator of the pres- 5 ent invention are provided with an inlet header Hl and an outlet header II, which are constructed of any suitable metal, but which are preferably made of cast brass. These headers are substantially rectangular in shape and have open 10 sides to which tube sheets I2 and I3 are respectively secured as by Welding along their peripheral edges to the edges of the associated header. rIhe headers are provided with inlet and outlet connections I4 and I5, respectively, by means of 15 which pipe connections may be made to the radiator.

Threaded sockets I6 are provided in the headers `for receiving suitable bolts by means of which the entire radiator assembly may be sup- `20 ported in operative position. Extending between the tube sheets I2 and I3, there are provided a plurality of streamlined tubes II of substantially ovate cross-section, which are normally disposed With their broadest edges facing against 25 the stream of theruid medium being circulated through the exterior of the radiator. These tubes are spaced apart transversely of the radiator and have their ends respectively supported in the tube sheets, the ends being secured to the 30 associated sheets by welding or other suitable means.

Transversel'y extending across the radiator are a plurality of fins I8 which are arranged in parallel closely spaced relation to provide large 35 surface contact areas for engagement by a fluid medium circulated through the radiator. These fins are of sufficient width to extend above and below the extremities of the streamlined tubes I1, and are provided with flanged openings 40 through which the tubes I1 extend. These anged openings are shaped to conform to the outer surface of the tubes, and the flanges at these openings abut the outer surface of the tubes. f

The tubes Il are connected in series to provide a serial flow path for the main steam supply in passing from the inlet header to the outlet header.

The series connection of the streamlined fin supporting tubes is accomplished by alternately connecting adjacent tubes in the inlet and outlet headers by means of end caps as shown at I9.

These caps are secured in any appropriate man- 55- ner, as by welding, at their peripheral edges to the associated tube sheet.

It will be noted that the caps I9, in addition to forming return end connections between the tubes II so that steam flowing therethrough will traverse the radiator in multiple reverse passes, also forms an auxiliary tube sheet for Supporting ends of tubes 2D, 2I, 22, and 23. These tubes are disposed within the tubes I1 for a purpose which will later be explained in detail.

In the case of tube 20, this tube extends through the associated cap I9 disposed in the inlet header and has this end open to receive steam directly from the inlet header. The other end of tube 2B is closed by a cap 24, which also closes the associated end of tube I'I. This end of the tube 20 is provided with an unrestricted opening 25 to enable flow of steam from the tube 20 into tube I'I, whence it is conducted back towards the inlet header and into the next tube II from whence it is conducted toward the outlet header. This steam continues to flow 4 back and forth between the headers and is carried from the left side of the radiator as shown in Figure 1 towards the right side thereof.

The last tube I'I, as shown in Figures 3 and 4, is closed at its outlet end by a cap 26 which also closes the associated end of the inner tube 23 disposed therein. Since the cap 26 only partially closes the tube II, an opening 21 is defined at the end of this tube which permits the steam which has followed the series path through the radiator to be discharged into the outlet header.

Moreover, since there are no openings into the series iiow path formed by the tubes II, which are disposed above the inner tubes therein, the spaces in the tubes I'I above the inner tubes therein form an air pocket which will prevent the tubes I'I from being completely filled with water, when the radiator is for any reason flooded.

The ends of the tubes 2I and 22 which are supported in the -cap I9 in the outlet header have thes'e ends closed-by tube end caps 28, which fit over the ends of the tubes and are secured as by welding around their peripheral edges to the associ-ated cap I9. The opposite ends of tubes 21| and 212, as well as the corresponding end of tube 23 are similarly capped, except that the'se caps are provided with restricted openings 29 which permit restricted amounts of steam to enter the tubes 2|, 22, and 23 directly from the inlet header. The total area of these openings is less than the internal area of the tube.

The tubes 2-I, 22, and 23 are supported attheir ends in the caps 28 against rotative movement and are held in lixed position by means of inwardly deflected portions 30 and 3lI in nested relation on the cap and tube respectively, as clearly shown in Figure 5.

`The tubes 20 t-o 23 are provided with small steam outlet holes along their bottoms, these holes or openings being longitudinally spaced throughout the length of the tubes. These outlet openings permit steam to be discharged from the inner tubes into the streamlined outer'tubes in a plurality of jets in a direction towards the bottom of the outer tubes.

With the foregoing arrangement, restricted amounts of steam are bled directly from the inlet vheader and distributed equally the whole length of the streamlined tubes. Due to the uniform path for steam traversing the streamlined tubes, the `flow of steam serially therethrough and the parallel ow of steam through the inner tubes, and through the jets into the streamlined tubes, tends to carry air along with it and keep the streamlined tubes clear of air, so that heat may efliciently be transferred to the nsassociated with the streamlined tubes. The jets of steam entering the streamlined -tubes will cause little disturbance in any air which may be in the streamlined tubes, and the air together with any condensate in the outer tube will be carried along and discharged into the outlet header through the opening 21.

With the arrangement previously described, there will be a differential of pressure between the various parts and the radiator. The highest pressure will be in the inlet header and the lowest pressure in the outlet header, the pres- -sure gradually decreasing as the steam passes through the streamlined tubes from the inlet to outlet header. The pressures in the inner tubes will be less than the inlet header pressure, but greater than the pressures in the outer tubes;

My improved radiator constructionis particularly adapted for the various conditions of operation which are met with in air conditioning apparatus. When the steam valve is wide open and ample steam pressure is supplied to the radiator, the steam will flow rapidly through tube 20, through the opening 25 into the series connected outer tubes, and be discharged through opening 2'1 into the outlet header. This steam 30 will discharge all condensation accumulated in the tube I'I from the steam in its serial passage through the radiator. The accumulated condensation `will be carried into the outlet header where it may pass through the outlet connection I5. Under these conditions of operation, a suicient volume of steam is supplied to induce a gentle current through the whole series of tubes and Iassure the elimination of air, which in arrangements heretofore provided has been mostly a hit 40 and miss proposition, the object of which was rarely attained.

Under throttled conditions of operation, the tube 20 distributes a minimum volume of steam, for example 10%, the whole length of the radia- 45 tor and also feeds steam to the series connected streamlined` outer tubes as volume increases'.

Auxiliary steam is supplied through tubes 2I, 2.2, and 2'3 to give maximum 'capacity to the radiator. This steam also serves to defrost and heat the condensation liquid, when starting up, as well as when the radiator is throttled to such an extent that only a part of the outer tubes would be heated.

My improved arrangement is also particularly advantageous in that the air pockets which are formed in the upper spaces of the' streamlined tubes prevent these tubes from becoming completely filled with water should the radiator become iiooded.

This feature, combined with'the construction of the streamlined tubes, wherein sloping walls are obtained at the lower part of the tube, tends to protect the radiator against bursting strains from expansion of water when frozen;

Another feat-ure of my improved construction is that the 'inlet header provides an ample dirt and scale pocket to insure clean steam that will not clog up the steam passages, particularly the outlet openings 32 of the inner tubes.

From the foregoing description, it wi'llbe apparent that the herein described invention provides an improved heat exchange device, such as a radiator, which is especially'adapted for throttled operation when utilized for the con- 75 ditioning of cold outdoor air which may at times have a temperature bel-ovv freezing; in which heat will be dis-tributed throughout the full length of the radiator, even at extremely low steam pressures; in which the main steam flow will be from end to end of the radiator in a` plurality of serially `connected passes, and which includes improved means for bleeding auxiliary steamA into these passes to prevent freezing of condensate during throttled operation and assure heating of the radiator from end to end during low pressure operation; which embodies improved means for removing air from the radiator; which is so Constructed .as to prevent the tubes from becoming completely filled with Water in the event that the radiator should become flooded; and which embodies improved fin and tube construction of such nature that ex-tremely low resistance will be offered to the circulation of a iiuid medium thereover, and in Which a high heat transfer may be eiected.

It is, of course, to be understood that although I have described in detail the preferred embodiment of my invention, the invention is not to be thus limited, but only insofar as dened by the scope and spirit of the appended claims.

I claim as my invention:

1. In a heat exchange device, a iiuid source, a plurality of double-Walled tubes, means for connecting the spaces defined by the inner and outer Walls of said tubes for iiuid iiow from said source therethrough in series, and connections to the spaces dened by the inner Walls of said tubes for parallel flow of fluid from said source therethrough.

2. In a heat exchange device, a fluid source, a plurality of relatively small tubes, relatively larger tubes respectively surrounding the smaller tubes, said larger tubes being connected for serial flow of fluid from said source therethrough, and a uid connection to said smaller tubes for parallel flow of iiuid from said source therethrough.

3. In a heat exchange device, a fluid source, a plurality of relatively small tubes, relatively larger tubes respectively surrounding the smaller tubes, said larger tubes being connected for serial flow of fluid therethrough from said source, and independent fluid connections from said source to said small tubes for parallel oW of iiuid from the source into said smaller tubes.

' 4. In a n and tube type radiator, fin carrying tubes serially connected for main steam flow, and inner tubes in said first tubes independently connected for parallel steam flow, said inner tubes having bottom perforations for feeding relatively small quantities of steam directly into the interior of the rst tubes to prevent freezing of condensation, When the supply of steam to the radiator is throttled to such extent that it will not pass through all the series connected first tubes.

5. In a heat exchange device of the iin and tube type, a plurality of large fin carrying tubes connected for serial now of steam through the device, and a smaller tube in each of the large tubes connected to the steam supply and having an outlet into its associated large tube, the small tube in the nrst large tube of the series having an unrestricted inlet and outlet, and the remaining small tubes havingrestricted inlets and outlets, vvhereby restricted amounts of steam are bled into the large tubes to promote distribution of steam through the entire length of the device and prevent the freezing of condensate by a cold medium passing over the fins, when there isinsufficient pressure to force steam the entire length of the series connected large tubes.

6. In a tube and fin type radiator, n carrying outertubes connected for serial flow of a main steam supply, and inner tubes respectively disposed in said outer tubes and having inlet connections to the steam supply for parallel flow of auxiliary steam into the outer tubes, one of said inner tubes having an unrestricted inlet for feeding the series connected outer tubes, and the remaining inner tubes having restricted inlets.

7. In a radiator, a steam supply header, main tubes in series connected to said header, auxil iary tubes in the main tubes connected in parallel to said header, and steam supply inlets to said tubes arranged to effect steam pressures in the auxiliary tubes which are less than the pressure in the header but greater than the pressure in the main tubes.

8. A heating method which comprises successively conducting a heated fluid from a high temperature fluid source through series connected heat absorbing ilo-W paths having alternately reversed directions of flow, and the subsequent raising of the temperature of said fluid at points along said paths', as the temperature of the uid is decreased, by the addition of other fluid from said source having a, relatively higher temperature than the liuid in the said paths.

9. The method of protecting a tube type radiator from freezing when throttled to such extent that the steam pressure is insufcient to for-ce main steam flow completely through the tubes, which comprises bleeding auxiliary steam directly througha relatively shorter path into the tubes at spaced points along the oW path of the main steam.

10. The method of protecting a tube type radiator from freezing when throttled to such extent that the steam pressure is insuihcient to force lmain steam flow completely through `the tubes, which consists of applying auxiliary heat at spaced points along the liovv path of the main steam.

11. A radiator unit comprising means defining a pair of eccentrically disposed main fluid flow paths connected in series through a relatively large opening for iiuid flow in opposite directions in said paths, the temperature of the iiuid in one of said paths being relatively greater than the temperature of the fluid in the other of said paths, and a relatively small bleeder connection opening between said paths disposed ahead of the series flow connection opening for injecting a portion of the highest temperature fluid into the lowest temperature uid.

l2. In a radiator, an inlet end header, an outlet end header, a plurality of n carrying tubes having their ends respectively supported in said headers, said tubes being laterally spaced apart, means connecting said tubes in series at said headers, the iii-st and last tubes of the series having ow connections respectively for receiving iiuid from the inlet header and discharging fluid into the outlet header, whereby fluid flow from inlet to outlet will be successively through said tubes in alternately reverse passes between said headers, and means for bleeding inlet fluid into the uid passing through said tubes.

13. A steam radiator comprising a steam inlet header, an outer header, a plurality of streamlined n carrying tubes of substantially ovate cross-section having their ends connected for series oW from the inlet header to the outlet header, each of said tubes having a greaterheight than width and being disposed with its thickest edge forming the tube bottom, and an inner tube in each of the rst tubes closed at the one of its ends lying adjacent the outlet header and connected at its other end to receive steam from the inlet header, said inner tubes respectively having steam outlet openings for directing steam therefrom in a direction towards the bottom of the associated outer tube, whereby all the ns and water passing through the radiator will be tempered equally from end to end of the radiator.

14. In a heat exchange device having a plurality of fin carrying tubes, means arranged to induce serial ow of a main steam supply through the fin carrying tubes from an inlet header to an outlet header, and means including separate steam connections connecting the inlet header with each of said tubes to supply auxiliary steam directly-to each tube from the inlet header for defrosting purposes.

15. In a radiator construction, a steam supply header having a wall portion defining a tube sheet, a pair of tubes each having one of its ends supported in the tube sheet, a cap member on the inner face of the tube sheet disposed over the adjacent ends of the tubes for connecting them for serial flow, and relatively smaller tubes respectively disposed in the first tubes, each of the smaller tubes having an end supported in the cap and connected to receive steam from the steam space in said header.

16. In a radiator construction, a steam supply header having a Wall portion dening a tube sheet, a pair of tubes each having one of its ends supported in the tube sheet, a cap member on the inner face of the tube sheet disposed over the adjacent ends of the tubes for connecting them for serial flow, relatively smaller tubes respectively disposed in the first tubes, each of the smaller tubes having an end supported in the cap and connected to receive steam from the steam space in said header, and outlet passages in the smaller tubes for bleeding steam into the associated I'lrst tubes.

1'7. In a radiator construction, a steam supply header having a, Wall portion dening a tube sheet, a plurality of relatively large tubes each having one of its ends supported in the tube sheet, cap members on the inner face of the tube sheet connecting said tubes in pairs and closing their ends relative to the steam space in said header, and a plurality of relatively smaller tubes respectively disposed in the smaller tubes, each of the larger tubes having an end supported in the associated cap and communicating with the steam space in said header.

18. In a radiator construction, a steam supply header, a steam outlet header, each of said headers having a Wall portion defining a tube sheet, a plurality of relatively large tubes having their ends respectively supported in said tube sheets, cap members on the inner faces of said tube sheets connecting the tubes for serial flow and closing the associated ends of the tubes relative to the steam spaces of the headers, a plurality of relatively smaller tubes respectively disposed in the large tubes with their ends respectively support-ed in the caps at the inlet header and outlet header, said smaller tubes having their ends at the outlet header closed and their ends at the inlet header communicating with the steam space therein, and steam outlets in the smaller tubes enabling discharge of steam therefrom into the large tubes.

ARTHUR F. HUBBARD. 

